Ultrasound Screening for Congenital Cardiac Defects

Ultrasound screening for anatomic abnormalities is routine in most areas of the United States. The specialties of providers performing the examinations are often regionally varied, with radiology performing examinations in some areas, general obstetrician gynecologists in others, and in a few areas, maternal fetal medicine (MFM) providers perform the screening ultrasound services. The quality of ultrasound equipment has improved dramatically over the past decades. However, the interpreting providers must be competent in the reading of imaging and know when further evaluation is needed. There are organizations that provide certification of prenatal imaging laboratories, such as the American Institute for Ultrasound in Medicine. Part of the certification processes is to ensure that ultrasound technologists are adequately trained and able to acquire appropriate images, as well as the need for continuing education in ultrasonography for physicians. The certification process may not be feasible for all practices but does provide a means of assessing competency verification.

As part of the general screening of all fetuses, we advocated for acquiring a four-chamber view, outflow tracts, arches, and a three-vessel trachea view. When a cardiac abnormality is suspected or the risk is sufficiently high based on maternal risks, fetal genetics, or family history, a detailed fetal cardiac examination is warranted. This is typically performed by either MFM providers or pediatric cardiologists with a specific interest and training in prenatal cardiac imaging. Fetal echocardiography will provide additional cardiac structural views and functional assessments, with the goal of optimizing diagnosis as much as possible before delivery.

When a fetal cardiac defect is found, the pregnant patient and her family will need additional follow-up and support. In our organization, if the defect is seen initially by MFM, we refer the patient to the fetal cardiology department for the next available appointment. We have a multidisciplinary team consisting of MFM, pediatric cardiology, neonatology, genetics, and pediatric cardiovascular surgery that is available to counsel patients. It is not uncommon for the initial shock of the diagnosis to create a barrier to processing information. Thus parents are often brought back to discuss findings again in a few days or a week later.

After confirming as well as possible the prenatal diagnosis, the team counsels the patient regarding expectations in the early neonatal period and longer-term outcomes. We have a fetal coordinator who is a registered nurse and takes patients through the neonatal intensive care nursery (NICU)/pediatric intensive care nursery (PICU) as appropriate to familiarize the family with the location. As much as possible, we attempt to make plans and contingencies that will be followed known to the patient and her family so that the element of surprise is reduced after delivery. Close contact with the primary obstetric provider is important to continue to support the family and as a means of following up with patients who may withdraw upon receiving bad news.

Our multidisciplinary team meets regularly to go over upcoming patients and to help determine the immediate neonatal plan. As pregnancy progresses, the plans may need to be updated as the condition or diagnosis evolves. The plan is relayed to the obstetric providers, neonatal providers, and facilities where delivery is anticipated.

Care of the Fetus/Neonate With Critical Cardiac Defects

In rare cases, such as fetuses with suspected hypoplastic left heart and restricted atrial septum or transposition of the great arteries with intact septum, an early septostomy may be needed. In these cases delivery in a facility that can provide this emergent procedure may be lifesaving for the child. In these cases abdominal delivery to provide logistic support may be considered as part of the management of the fetus. For example, in some centers, delivery may be performed in the children’s hospital or regional maternity hospital with the pediatric catheterization laboratory held open to receive the newborn. The coordination of the resources needed for these deliveries is often intense. Facilities that choose to perform these procedures should have active ongoing training programs and case review for improvement in process. If uncertain whether the child will need immediate intervention, it is better to transfer to a facility for delivery that can handle the emergent procedure if necessary.

Neonatal Resuscitation Program and the Critical Congenital Heart Defect Screen

Although changes in prenatal assessment and technologies can help to improve care and outcomes for babies with CHD, they can pose several challenges at many different levels for providers of both maternal care and newborn care. Providers are responsible for making sure that the necessary technologies and training are made available to support both maternal and newborn care. Two important initiatives are the Neonatal Resuscitation Program (NRP) and the Critical Congenital Heart Defect Screen.

The NRP, sponsored by the American Academy of Pediatrics (AAP), is an evidence-based approach focusing on resuscitation skills for the newborn. The NRP provides a basic algorithm for neonatal resuscitation, offering effective team-based care for health care providers caring for newborns at birth in the delivery room or nursery. It is essential that health care providers caring for newborns obtain and maintain NRP training.

The Critical Congenital Heart Defect Screen is a tool for early detection of critical congenital heart defect (CCHD). Eighteen out of every 10,000 babies are born with CCHD, which requires early intervention. Because CCHD may not be detected prenatally or upon examination, there is a risk that infants with CCHD may quickly decompensate when discharged from the nursery to home. CCHD screening has been found to be an effective way to detect serious health issues in what appears to be a well newborn. The AAP recommends screening after 24 hours of age or right before discharge if the baby is less than 24 hours of age. All babies at risk for undetected CCHD should be screened, which would be any baby that is not known to have CCHD.

Levels of Newborn Care

There are four levels of care for newborn infants: level I, well-newborn nursery; level II, special care nursery; level III, NICU; and level IV, regional NICU. The majority of babies are born in a lower level of neonatal care, so it is necessary to have a basic line of service to manage a potential congenital heart defect and to be prepared for an emergency. This service would include having NRP-certified personnel present at all deliveries and the ability to do CCHD screening. Essentially there are two scenarios for the birth of a baby with a complex cardiac defect. One scenario is the unknown and undiagnosed cardiac defect with or without cardiovascular compromise that may or may not initially be obvious to the clinician and is asymptomatic at birth. The second scenario is the birth of a baby with a known diagnosed complex cardiac defect.

Unknown Cardiac Defect Preparation

The more frequent scenarios are those in which there has been limited or no prenatal screening and a baby is born with an unidentified cardiac defect. These babies can develop a rapidly deteriorating cardiovascular compromise with or without cyanosis. In this case it is critical to have several processes in place: rapid access to cardiac consultation, preferably in person with a pediatric cardiologist or a consult via telemedicine; access within 60 minutes to an echocardiogram; and a provider who is competent in managing basic airway support and intravenous (IV) access. Additionally, it is important to have available lifesaving medications such as prostaglandin and personnel that are trained to prepare and administer the drug. Personnel should also be familiar with code medications that are routinely used when providing NRP. In addition to providing emergent treatment, it is important to have an established referral agreement with other units that can provide a higher level of care and availability of a transport system that can expedite and facilitate transporting the infant to a tertiary center.

Known Cardiac Defect Preparation

When a pregnancy has been diagnosed with a complex heart defect, it is imperative to discuss the findings, the potential outcomes, and the medical options with the family. There may be a case in which the mother-baby dyad needs to be comanaged with a MFM specialist group that is specialized in obstetric care and competent, certified, and experienced in the care of fetal complications. Special attention should be given to the option of a planned delivery in which multidisciplinary care can be provided for both the mother and baby. This field is rapidly changing, and it is now becoming a common practice for MFMs, along with pediatric cardiologists and neonatologists, to manage fetal congestive heart failure and arrhythmias that otherwise would either affect the outcome of the baby or end up in a premature delivery. It is also important to have access to interventional cardiologists, pediatric cardiovascular anesthesiologists, pediatric cardiovascular surgeons, pediatric cardiac intensivists, and ECMO. Other important ancillary services include genetics, a chaplain, and a dedicated PICU and NICU specialized in congenital heart defects. When the mother is referred to a tertiary center, it is important to have the support of social services and case workers who can assist with relocation, housing needs, care for other siblings, and financial assistance. Ideally, these patients are triaged before birth so that bonding (yes/no), emergent lines (yes/no), PGE dependence, and admitting unit (PCICU/NICU) are all determined before delivery. This ensures that appropriate triage is performed before delivery.